It is known that UCN-01 has protein kinase C inhibitory activity [J. Antibiotics., 40, 1782 (1987)] and has anti-tumor activity [Cancer Res., 51, 4888 (1991)]. Further, it is disclosed in WO89/07105 that the UCN-01 derivative possesses inhibitory activity on cell growth.
In case UCN-01 or its derivative is administered in vivo particularly to blood vessels, it would be impossible to prevent UCN-01 or its derivative from contacting vascular cells and other various normal cells, as well. Because the UCN-01 derivative has inhibitory activity on cell growth, the contact of UCN-01 or its derivative with normal cells may cause certain adverse effects on normal cells.
In case UCN-01 or its derivative is administered as such to blood vessels, the compound may undergo decomposition in blood or be accumulated in internal organs other than the target, and is thus not necessarily accumulated in tumors effectively
Also, the compound may bind thightly onto the serum components before accumulation in the target turmors.
There is demand for a preparation containing UCN-01 or its derivative, which is stabilized in blood and accumulated at high levels in tumors without causing any effect on normal cells.